如何将StringWriter中的值转换为XML格式？

Question

I have written a Service and in the I need a return type as n XML which I will passing to Client. I am having Values in string writer as - <newdataset> <table> <Slno>1</Slno></table><Name>Andrew</Name><table><Slno>2</Slno><name>Trisha</name></table></newdataset>

What I need to return is a proper XML format from the service to the client.

PS - It should have a header like all the XMLs has -- like this : < ?xml version="1.0" standalone="yes"?>

Thanks,

Nayan

Answer 1

Use the DataTable.WriteXml(XmlWriter) overload. Then when creating the XmlWriter you can pass in an XmlWriterSettings with the necessary formatting options, including setting settings.OmitXmlDeclaration = false (which is actually the default). Thus:

    public static string ToXml(this DataTable dt)
    {
        using (var textWriter = new StringWriter())
        {
            var settings = new XmlWriterSettings();
            settings.Indent = true;
            settings.IndentChars = "    ";
            // settings.OmitXmlDeclaration = false; not necessary since this is the default anyway.
            using (var xmlWriter = XmlWriter.Create(textWriter, settings))
            {
                dt.WriteXml(xmlWriter);
                return textWriter.ToString();
            }
        }
    }

Thus gives the output:

<?xml version="1.0" encoding="utf-16"?>
<newdataset>
    <Name>Andrew</Name>
    <table>
        <Slno>1</Slno>
    </table>
    <table>
        <Slno>2</Slno>
        <name>Trisha</name>
    </table>
</newdataset>

The same will work for a DataSet as well if you have one. (For reasons unclear to me, the WriteXml(TextWriter) overload omits the XML declaration.)